A．proficiencyB．efficiencyC．affectionD．effective

单项选择题

Boeing Co’s Sonic Cruiser, a proposed faster airliner, would be mostly blended material, program director Walt Gillette said recently. In its quest for the (21) to fly 15 to 20 per cent faster than (22) airliners, the US company says about 60 per cent of the new plane’s (23) , including the wing, would be a carbon-fiber-reinforced composite material that is lighter than aluminum for the same (24) . "Composites would (25) almost all of the airplane that you could see from the outside," Gillette said. Composites are well regarded among aeronautical engineers and have been in (26) use since the 1970s. Each generation of planes has more composites, and Gillette (27) that about 10 per cent of Boeing’s (28) civil aircraft, the early-1990s 777, is built (29) the material. (30) still only a proposal, the Sonic Cruiser has (31) the interest of many airlines, which expressed unusual enthusiasm for the aircraft (32) the September 11 attacks forced most of them to scale back operations. When Boeing (33) the Sonic Cruiser last year it said the plane might enter service (34) 2006 and 2008. Gillette said the (35) date now is 2008, by which time the market and technology are expected to have developed (36) Wind-tunnel tests (37) the company’s computer calculations of optimal cruising speed for the plane at 95 to 98 per. cent of the speed of sound. Going faster than sound would use too much fuel and (38) great (39) on the aircraft’s engines. Gillette said the Sonic Cruiser (40) be offered as a family of aircraft with 200 to 250 seats and a range of 6,500 to 9,000 nautical miles (12,000 to 16,700 kilometers).

A．proficiency
B．efficiency
C．affection
D．effective